1. Field of the Invention
This invention relates to modems, and particularly to wireless modems, that is, modems designed to transmit digital data over radio links.
2. Review of the Art
Typically, wireless modems have been relatively unsophisticated, essentially comprising a combination of a modem similar to those used to transmit data over voice telephone lines with a radio transceiver similar to those used for radiotelephony. Particularly when such modems are used for unattended communications, as between telemetry systems and a monitoring station, it has been difficult to monitor the quality of the radio link or the proper operation of, the modem, both during set-up or maintenance of the system and during actual operation.
There is therefore an increasing demand for an economical wireless modem which allows for such monitoring. In order that wireless modems from different sources be interoperable, it is also desirable that such modems should utilize standardized communication protocols, enabling modems of different makes to intercommunicate.